Remainder theorem states that “If a polynomial f(x)is divided by x — k, then the remainder is the value f(k)”
We can use polynomial division to evaluate polynomials using the Remainder Theorem. If the polynomial is divided by x - k, the remainder is r, then this value equals the value of the polynomial function at k, that is, f(k). So this helps to evaluate the polynomial at a given value of x. Since the division is done by a linear factor, we can use the synthetic division method.